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Leap Year/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby A boy, Tim, is seated at his kitchen table reading Upton Sinclair's novelOil! A robot, Moby, appears. He is holding a wrapped present. MOBY: Beep. TIM: Oh, wow. A gift for me? MOBY: Beep. Moby hands Tim the present. TIM: Well, happy belated President's Day to you, too, buddy. Tim unwraps the present. It is a swimsuit calendar. As Tim flips through the pages he sees pictures of actual swimsuits, with no models wearing them. TIM: Wow, Moby. This is pretty, uh, huh. MOBY: Beep. Moby hands Tim an envelope. Tim reads from a typed letter. TIM: Dear Tim and Moby, Why do we have leap years? Sincerely, Maia. (Brooklyn, NY) TIM: Hey, Maia, thanks for writing in. The reason why we have leap years is pretty simple. The time it takes the earth to make one complete revolution around the sun is called a solar year. On average, a solar year takes 365 days, 5 hours, 48 minutes, and 46 seconds. An animation shows Earth revolving around the sun as time elapses. MOBY: Beep. TIM: Well, you could just round it down and make the calendar year 365 days, but the time you skipped over wouldn't just go away. The extra time would accumulate, and you'd lose a full day every four years. An animation shows Earth orbiting the sun as the time counter's reading increases in increments of 5 hours, 48 minutes, 46 seconds. TIM: After a while, the seasons would no longer match up with the months, and the whole calendar would be thrown out of whack. An animation shows two warmly dressed people grilling hot dogs on a snowy beach. Fireworks explode, and a plane flies overhead pulling a banner that reads "Happy Fourth of July!" MOBY: Beep. TIM: Right. To make up for the extra time, we add an extra day to the calendar every four years. The extra days are called leap days, and the years in which they occur are called leap years. An animation shows a wall calendar displaying the month of February. There are 29 days in the month, and the 29th is circled. TIM: This practice was made official by Julius Caesar, the Roman dictator, in 45 B.C.E. Caesar reformed the imprecise Roman calendar into the 12-month, 365–day format that we use today. This included the addition of a leap day every four years. An animation shows Julius Caesar chiseling new dates into a large stone calendar. TIM: His Julian calendar worked pretty well for a while, but there was one major problem. MOBY: Beep. TIM: No, it wasn't that the Roman numerals were too bulky. An image shows a stone tablet, inscribed to represent the month of February. The individual dates appear as Roman numerals. TIM: It was that the calendar year still didn't match up with the solar year. Side-by-side images show the Roman calendar with the Julian year being 354 days and 6 hours, and the earth orbiting the sun with the solar year being 365 days, 5 hours, 48 minutes, and 46 seconds. TIM: Because of this error, the calendar was still gaining a full day every 128 years. It may not seem like much, but after more than 1,000 years the extra days began to add up. The vernal equinox, or first day of Spring, was supposed to fall on March 21, but by the late 1500s it was moving closer and closer to February. An animation shows the sun and Earth in space. A calendar illustrates the shift in vernal equinox that Tim describes. TIM: The lost time made it hard to set the dates of religious festivals. An image shows a religious figure in front of a large church. TIM: So, in 1582, Pope Gregory the XIII announced a change. Pope Gregory XIII holds up a wall calendar labeled "Awesomest New Calendar." TIM: In the Gregorian calendar, there would be a leap year every four years, with one important exception. Years ending in "00" would not be leap years anymore, except if they were divisible by 400. An animation displays rows of years in the Gregorian calendar and highlights the years Tim describes. TIM: That's the system we use today. It's not perfect. The calendar still loses a day every 3,200 years or so. But it works pretty well. MOBY: Beep. TIM: Oh, that's easy. Except for those special "00" years, leap years always fall on years whose last two digits are divisible by four, like 2004, 2008, 2012. You get the picture. An animation shows a range of years and highlights the years Tim mentions. MOBY: Beep. TIM: Well, the Gregorian calendar was adopted at different times in different countries. To reset the vernal equinox at March 21, some countries dropped days off the calendar. An animation shows a farmer scratching his head as he stands in his field holding a calendar. He is studying the month of September. TIM: In Great Britain and the United States, the year 1752 only had 354 days. September 14 fell one day after September 2. A calendar shows September, which goes from the 2nd to the 14th. MOBY: Beep. TIM: That's right. Today the Gregorian calendar is used all over the world. But many cultures calculate the dates of festivals and religious observances with older, traditional calendars. Those calendars deal with leap years in different ways. Like, the months of the traditional Chinese calendar and the Hebrew calendar are based on the cycle of the moon. An animation shows night in the Chinese countryside. The moon goes from a crescent sliver to a full moon, and then returns to a sliver. TIM: There are 12 short months, and an extra month is inserted every two or three years to keep things orderly. Wall calendar pages display "Month 1," "Month 2," "Month 3," and then "Month 3a," "Month 4," and so on. MOBY: Beep. Moby's chest opens, showing a monitor screen that reads "28." TIM: You know, I was gonna ask you if you had an internal calendar. MOBY: Beep. TIM: Does it do anything special for leap year? MOBY: Beep. Moby looks downward at his chest. The date on his monitor changes to "February 29." A cuckoo-clock sound is heard, and a door below the monitor screen opens. Frogs leap out and onto the kitchen floor, one by one. FROGS: Ribbit. Ribbit. Ribbit. TIM: Wow. I really should have seen that one coming.Category:BrainPOP Transcripts Category:BrainPOP Social Studies Transcripts